Contents

Introduction

In this chapter I
venture rather far away from my areas of expertise and present some
ideas that I have read about and believe on the basis of
generally-accepted scientific consensus. The ideas, in brief, are
these:

There is a level
of physical reality at which things and events are quite tiny, less
than about 100 nanometers long. This level is called the "quantum"
level of reality.

Things and events
at the quantum level of reality behave differently from things and
events that are larger. They are indeterminate, meaning that the
outcomes of events cannot be predicted in advance, except in
statistical terms. In other words, an initial configuration of
things and forces does not determine a subsequent configuration.
Mathematics can describe the probability of a range of outcomes, but
cannot predict a single outcome.

The synapses in
the human brain are small enough – about 20 nanometers –
that quantum indeterminacy operates there. Distances within the
neuron where critical events such as the influx of calcium ions
happen are even smaller. Hence it is in principle not possible to
predict whether any given neuron will fire or not.

Our thoughts,
perceptions, emotions and intentions are correlated with neural
functioning. Once something happens at the synaptic level of the
brain, ordinary physical causality takes effect and we experience
thoughts and feelings, etc. But what initiates those thoughts or
feelings is not pre-determined.

From these ideas I
infer the following:

It does not
contradict scientific knowledge to say that something nonphysical
determines whether a neuron will fire or not. Thus, it does not
contradict scientific knowledge to say that the quantum level of
reality is where something nonphysical intervenes in the physical
world.

Quantum
Physics

"Quantum" is
a word derived from the Latin word meaning "how much.” In
this context it refers to a characteristic of things that are very
small, less than 100 nanometers long. The magnitudes of certain
properties of such things can take on only discrete numerical values,
rather than any value, at least within a range. For example, the
energy of an electron bound to an atom at rest is quantized, so
electrons orbit their nuclei only at certain discrete distances, not
in between. This accounts for the stability of atoms, and matter in
general. Light also is quantized. A photon, being a unit of light, is
a "light quantum.” Quantum Mechanics is the field of study
of physical reality in such small dimensions, and we call this the
"quantum level" of reality.

Things behave very
strangely at the quantum level. We can't see them with the unaided
eye, of course, but we can detect them through instrumentation, and
their properties and behavior can be described mathematically by a
formula called the "wave function.” Under certain
circumstances the wave function divides into two or more pairs or
branches, each with its own consequences. Each of these branches
represents a potential future or a potential version of reality. When
observed, only one of these branches is perceived; that is, only one
of the potential futures becomes the actual perceived present.

There are some famous
experiments, which have been widely replicated, that reveal the
strangeness of this level of reality. Two of them are the Double-Slit
experiment and the Stern-Gerlach experiment.

The Double-Slit Experiment

The Double-Slit
experiment consists of sending a beam of coherent light1
through two side-by-side vertical slits to a recording medium, such
as film. It illustrates that light can behave both as a stream of
particles and as a wave. When light is sent through one slit at a
time, a vertical band appears. Light acts like a series of particles
that go through the slit, hit the recording medium and make an
impression. If the experimenter opens the slit on the right, the band
appears on the right, and if the experimenter opens the slit on the
left, the band appears on the left. One would expect that if both
slits were opened, the result would be two side-by-side bands. In
fact, however, the result is a strong band in the middle, the
expected bands on the left and right, and then dimmer bands extending
outward in each direction. Light in this case acts like waves that
cause interference patterns. That is, when a crest meets a crest, a
more intense crest results; and when a crest meets a trough they
cancel out. The bands of light are from the crests reinforcing each
other, and the darkness in between is the from crests and troughs
canceling each other out.

Even more interesting,
when light is emitted one photon at a time and aimed at the two
slits, it shows the same interference pattern. One would expect that
a photon would go through one slit or the other. In fact it appears
to act like a wave that goes through both slits, interferes with
itself, and results in an impression in one and only one of the
bands.

One cannot predict in
advance in which band the photon will make an impression.

One can predict that
given a great number of photons, they will result in bands. That is,
they won’t all end up in the same place, but rather in various
places according to their probability distribution. But there is only
a probability, not an absolute certainty, that any single photon will
end up in one place or another.

One of the questions
engendered by this experiment is what causes the wave, which is
mathematically described as a collection of probabilities of being
detected in various places, to be in fact detected at only one place.
I’ll return to this question later. For now, note the “quantum
indeterminacy,” our inability to predict the final location of
any single photon. A photon is not like a billiard ball. If you know
the mass of two billiard balls, the amount of force and its direction
applied to one, and the angle at which it hits the second, you can
predict in what direction and how fast the second ball will travel.
Not so with quanta.

The Stern-Gerlach Experiment

The Stern-Gerlach
experiment, named after the scientists who first performed it,
consists of sending a series of electrons through an inhomogeneous
magnetic field, which deflects them. On the other side of the field
from the emitter is a recording medium, which registers where the
electron hits the medium. Each electron is detected at one of two
places on the medium, depending on what is called the “spin”
of the electron. An important finding of this experiment is that
electrons are detected in only two places rather than in a range
between them. Thus, an electron’s spin can take only two
values; it is quantized. This corroborates the quantum nature of
reality at this level.

Another finding is
confirmation of quantum indeterminacy: one cannot predict in advance
in which place the electron will be detected.

Again, given a great
number of electrons and the known characteristics of the magnetic
field, one can predict the relative number of impressions at each
detection point. But there is only a probability, not an absolute
certainty, that any single electron will end up in one place or
another.

Causal
Discontinuity

At the quantum level of
reality there is a radical discontinuity of causality. Here are some
descriptions:

“The mathematics of quantum mechanics does not predict which
path will be taken. This is the indeterminacy, or randomness, of
quantum mechanics.” (Blood, Science Sense and Soul, p.
64)

“. . . in what sequence members of a series of singly emitted
things (e.g., electrons) will arrive is completely unpredictable.”
(Wikipedia, “Double-slit experiment”)

“The electrons (and the same applies to photons and to
anything of atomic dimensions used) arrive at the screen in an
unpredictable and arguably causeless random sequence . . . .”
(Ibid.)

“In quantum mechanics, the value of a physical quantity
(usually called an observable) cannot in general be predicted with
certainty.” (National Science Teachers Association, “The
Stern-Gerlach Experiment”)

“. . . the apparent random selection of which outcome state
[appears] remains one of greatest mysteries of science.”
(Wikipedia, "Consciousness Causes Collapse")

“. . . the appearance of there being an uncaused event
(because of the unpredictability of the sequencing) has aroused a
great deal of cognitive dissonance and attempts to account for the
sequencing . . . .” (Wikipedia, “Double-slit experiment”)

In ordinary life and in
classical (non-quantum) physics, we have a clear concept of
causality: a cause is something that reliably produces an effect.
Given the same or a similar set of circumstances, we expect the same
results to appear. Hitting the billiard ball at a certain angle and
with a certain force will always cause it to move in a certain
direction and at a certain speed. This conception of causality has
three parts:

Regularity –
A cause always produces its effect according to physical laws that
can be discovered by observation and experiment. (Here “law”
means observed regularity, not something moral or legal.)

Temporal Sequence
– The cause always precedes its effect in time. The cause
never follows the effect.

Spatial Contiguity
– There is always some physical connection or spatial contact
between the cause and its effect, or a chain of such connections.

At the quantum level,
the regularity is missing. There is no set of circumstances that
causes the photon or electron always to land in a specific place.

Once the photon or
electron has landed – that is, has been detected – then
the ordinary chain of causality takes over. "[T]he beginning of
a macroscopic event can be dependent upon a microscopic event. In
that case, each microscopic possibility at the beginning can lead to
a different macroscopic event at the end." (Blood, Science
Sense and Soul, p. 72) Physicist Erwin Schroedinger postulated a
famous thought-experiment: Put into an isolated chamber a cat, a
radioactive substance, a Geiger counter and a device that will kill
the cat when the Geiger counter is triggered. Whether an atom of the
substance will decay within an hour is indeterminate; thus during
that time the state of the cat is also indeterminate. Schroedinger’s
point, among others, was that this seemed absurd. Surely the cat is
either alive or dead, regardless of whether anyone observes it. My
point is merely that it is widely recognized that quantum events,
once they have become detected, are then determined and can cause
further events to happen.

But what causes the
quantum event to cease being merely a probability and start being
something that is detected and exists at a certain place? Not
anything in the physical world. Perhaps it is something nonphysical.
It is possible – that is, it does not contradict the scientific
evidence to assert – that something nonphysical decides which
probability to actualize.

This becomes important
when we consider that some events in the brain happen at the quantum
level.

The Brain

The human brain is a
mass of electrochemical activity. It contains approximately 100
billion nerve cells, or neurons, and up to five quadrillion
connection points between neurons. A neuron is the fundamental
element of the brain; it transmits electrochemical impulses to and
from other neurons, sense organs or muscles. Some impulses are
triggered by sense organs, and some by the excitation of neighboring
neurons. Some impulses excite or inhibit neighboring neurons and some
cause muscle contractions that move the body. Here is a picture of
one (Wikipedia, “Neuron”):

A neuron looks a bit
like a tree and consists of several parts: numerous dendrites (from
the Greek for “tree”), a cell body called soma (Greek
for “body”), and a single axon (from the Greek for
“axle”), which branches at the end to many terminals.
Dendrites are the incoming channels; they extend from the soma
and subdivide into smaller and smaller branches. Some nerve cells
have dozens of dendrites, and some have hundreds, depending on the
cell’s function. Dendrites receive electrochemical impulses
from other cells. These impulses pass through the soma and then out
the axon. The soma is the core of the nerve cell and contains
the elements common to all cells that keep it metabolizing,
synthesizing proteins, receiving nutrients and excreting waste, etc.
Each nerve cell has a single axon, a fiber that passes the
impulse from its terminals to synapses. A synapse (from Greek
roots meaning “to clasp together”) is a gap between
neurons only twenty nanometers wide. On the other side of the
synaptic gap, also called the synaptic cleft, is a receptor area on a
dendrite of a neighboring cell. An axon can have many terminals, and
each dendrite can have many receptor areas. Thus each neuron
transmits impulses to and receives them from a great many neighboring
neurons. As each one has many dendrites, some neurons receive
impulses from up to 10,000 neighbors. Some in the cerebellum receive
up to 100,000. Clearly the brain is an organ of almost unimaginable
complexity.

An impulse traveling
through the neuron is an electrical charge called an action
potential, which travels through the nerve at up to 200 miles per
hour. When this happens we say that the neuron “fires.” A
neuron either transmits the impulse or it does not; it is a binary
element, either on (firing) or off (not firing). When the electrical
charge reaches the synaptic cleft, it triggers the release of
neurochemicals; hence we call brain activity electrochemical. There
are more than sixty of these neurochemicals, called neurotransmitters
because they seem to transmit information from one nerve cell to
another. Some excite neighboring neurons and some inhibit them.

The end of the axon,
called the nerve terminal, contains vesicles, tiny containers
that hold the chemical neurotransmitters. The neurotransmitters are
released into the synaptic cleft when an electrical charge reaches
the vesicles. On the other side of the cleft, the dendrites contain
specialized receptors that bond to the neurotransmitters and cause
electrical activity when excited by them. This is how impulses travel
from neuron to neuron. When the electrical activity caused by
incoming neurotransmitters reaches a certain threshold, the neuron
fires and sends an action potential to its axon.

A single release of a
neurotransmitter might be too weak to trigger the action potential of
the receiving neuron, but since each neuron forms synapses with many
others and likewise receives synaptic inputs from many others, the
combination of several inputs at once can be enough to trigger it. Or
the receipt of an inhibitory neurotransmitter can prevent an action
potential that otherwise would have fired. The output of a neuron
thus depends on the input of many others, each of which may have a
different degree of influence depending on the strength of its
synapse with that neuron.

The mechanism by which neurotransmitters are released is of
particular importance.

Here is a picture:

Within the pre-synaptic nerve terminal, vesicles containing
neurotransmitter sit "docked" and ready at the synaptic
membrane. The arriving action potential produces an influx of calcium
ions through voltage-dependent, calcium-selective ion channels.
Calcium ions then trigger a biochemical cascade which results in
vesicles fusing with the presynaptic-membrane and releasing their
contents to the synaptic cleft. (Wikipedia, “Chemical synapse”)

The channels through
which calcium ions enter the nerve terminal from outside the neuron
are tiny, only about a nanometer at their narrowest, not much bigger
than a calcium ion itself. The calcium ions migrate from their entry
channels to sites within the nerve terminal where they trigger the
release of the contents of a vesicle. At this submicroscopic level of
reality, quantum indeterminacy is in play. A given calcium ion might
or might not hit a given triggering site; hence, a given
neurotransmitter might or might not be released; hence the receiving
neuron might or might not get excited (or inhibited).23

In other words, at the
most fundamental level, brain functioning is not causally determined.

This causal
indeterminacy pertains at quadrillions of synapses, each of which
contributes to the overall state of the brain. Submicroscopic events
trigger larger events, which are then causally determined. But the
initial events, the beginnings of chains of causality, are
indeterminate, and there are a great many of them. The whole state of
the brain can become a quantum cloud of uncertainty. Noted quantum
physicist Henry Stapp says

. . . a conscious brain … must be expected to evolve into a
state that represents a superposition of macroscopically different
alternative possibilities for the brain . . . . (Stapp, Mind,
Matter and Quantum Mechanics, p. 154)

. . . [T]here is no likelihood that during periods of mental groping
and uncertainty there cannot be bifurcation points in which one part
of the quantum cloud of potentialities that represents the brain goes
one way and the remainder goes another, leading to a quantum mixture
of very different classically-describable potentialities. . . . [A]ny
claim that the large effects of uncertainty principle at the synaptic
level can never lead to quantum mixtures of macroscopically different
states cannot be rationally justified. (Stapp, Mindful Universe,
pp. 31, 32)

To rephrase Stapp’s
double negative, quantum uncertainty at the synaptic level can lead
to causal uncertainty at the level of the whole brain.

Researchers have made
much progress in identifying the neural correlates of consciousness,
the patterns and groups of nerves that fire when certain experiences
take place. Brain scans reliably show the areas of the brain that
"light up" during perceptual tasks. Whether patterns of
neural firings cause conscious experiences or conscious experiences
cause patterns of neural firings or both is a matter of debate. Since
we live in a world of physical causality and we ourselves are
physical creatures, it seems reasonable to assume that the state of
the brain at least heavily influences, if not causally determines,
our perceptions, thoughts, feelings and actions. Anti-depressant
drugs, for instance, work by altering the chemistry of the synapse.

If there is causal
uncertainty at the level of the whole brain, then human conduct is
not fully causally determined in the physical world.

What causes a quantum
event – in this case the impact of a calcium ion on a
triggering site – to cease being merely a probability and start
being something that happens at a certain place? Not anything in the
physical world. Perhaps it is something nonphysical. It is possible –
that is, it does not contradict the scientific evidence to assert –
that something nonphysical decides which probability to actualize,
thereby exerting a causal influence on our experiences, our
perceptions, thoughts, emotions and actions.

Beyond the Causal Veil

There is a causal
discontinuity in nature. Events at the quantum level of reality have
no physical cause, but are themselves causes of subsequent events.
What is on the other side of the causal discontinuity?

At this point we move
beyond what physics can tell us. A number of things might be
appropriate here. With Wittgenstein, we could simply shut up about
it. Or we could postulate an incorporeal soul with free will or a God
that intervenes in nature or a multitude of deities. Science can
neither prove nor disprove such assertions. We must look elsewhere –
in introspective analysis of our own experience of making a choice,
for instance, or in patterns of coincidence or synchronicity –
for evidence. Such evidence would not hold up in the public court of
scientific inquiry, but might well be decisive for how we choose to
live our lives.

Some say that the
causal uncertainty at the quantum level of reality is merely
statistical. Events happen randomly; hence, no conclusion can be
drawn about nonphysical causality, free will, the existence of a soul
or of God, or any such thing. But random as they may be individually,
quantum events considered as a group certainly do exhibit
regularities. Light passed through double slits exhibits distinct
patterns, not random noise.

Consider a pointillist
painting, which consists of distinct dots of pigment. If you look at
it up close, all you see is random dots. When you view it from afar,
you see identifiable forms and shapes, recognizable objects. I
assert that the influence of the nonphysical on the physical world
could be like that. What appears to be the random firing of a neuron
may in fact be part of a larger pattern that extends through space
and time.

Each one of us must
determine for ourselves the nature and import of that larger pattern.

Fixed a typo. Added footnote on epistemology
and ontology and citations from Stapp, Mind, Matter and
Quantum Mechanics.

1.0

27 June 2008

Bill Meacham

First publication. No difference from v 0.4c.

1
“Coherent” means that all the light waves have the same
frequency; hence they can interfere with each other. Lasers emit
coherent light. If you shine an ordinary light through a small
pin-hole, the light that gets through is largely coherent as well.

2
Nerve terminals are not the only places that calcium ions have an
effect. Calcium ions play a major role in controlling the
functioning of all cells of the body. By entering the cell plasma
they cause the specific action of the cell, whatever this action is:
secretory cells release secretions, muscle cells contract, synapses
release synaptic vesicles, etc. Only in the nerve terminal does
quantum indeterminacy have a large effect on the activity of the
nervous system. Here the different triggering sites are very close
together and the macroscopic effects of the firing of different
nerves can be quite different.

3
This account of neural functioning assumes that what is observable
in carefully-controlled scientific experiments pertains as well to
parts of reality not directly observable. We cannot actually observe
the impact of a calcium ion on a triggering site because the act of
setting up the observation would kill the organism containing the
nerve being observed. I assume that the behaviour of reality is
consistent at the quantum level whether we can observe a particular
instance of it or not. In order to make that assumption I also
assume that the description of the quantum level of reality is not
only epistemological, pertaining to our experience of nature, but
ontological as well, pertaining to what actually happens in nature
whether or not a human being observes it. See the discussions titled
“Quantum Theory and Biology” and “The Heisenberg
Ontology” in Stapp, Mind, Matter and Quantum Mechanics,
pp. 123-128.